Thin film transistor liquid crystal display (TFT-LCD) has become a mainstream product on the market due to its features such as being light and thin, being space-saving, low power consumption, and low radiation. The liquid crystal display technique has currently been widely used in TVs, mobile phones and public information displays. For these products, the image quality has attracted more and more attentions, and the display evenness is an important one of the various parameters.
A liquid crystal display device includes an array substrate, a color filter substrate, and a liquid crystal layer arranged therebetween. Data lines and gate lines are arranged in a crisscross manner on the array substrate, so as to define subpixels at a display region of the array substrate. Each subpixel is provided with a TFT, a gate electrode of which is connected to the gate line, a drain electrode of which is connected to a pixel electrode, and a source electrode of which is connected to the data line. Under the collective action of a gate driving signal from the gate line and a data signal from the data line, an electric field is formed at the liquid crystal layer through the pixel electrode and a common electrode, and thereby liquid crystal molecules are controlled by the electric field to deflect so as to achieve the display.
For a traditional liquid crystal display device with a fringe field switching (FFS) mode, the pixel electrode and the common electrode are both arranged on the array substrate, and each subpixel is provided with one pixel electrode. The common electrode and the pixel electrode are insulated from each other and cover the entire display region. A common electrode line is arranged at a periphery of the display region of the array substrate, and connected to the common electrode so as to provide a signal thereto. However, there is the following defect in the traditional liquid crystal display device with the FFS mode. The common electrode uses a whole indium tin oxide (ITO) electrode, and due to its resistance, there is a great voltage drop of a common electrode signal between a region adjacent to the common electrode line and a region away from the common electrode line. As a result, the display evenness will be adversely affected.